Process for removing all forms of polluting substances from liquids



- Patented Sept. *26, 1933 ,raoonss FOR nncrovmc Am. roams on POLLUTING SUBSTANCES FROM ILKQEIEBS Oliver, M.- Urbain, Columbus, Ohio, assignor to Charles H. Lewis, Hamster, @hio hTo Drawing. Application June 2%, 193% 1 Serial No. 462,708

2 Claims.

The present invention contemplates the provision of a colloid chemical precipitation process which will separate from-polluted liquids such as sewage and industrial wastes, substantially one 5 hundred percent of the polluting substances contained therein, including all organic matter in its several forms, that is, normally suspended mat:

ter, colloidal matter in dispersion, and the matter in true solution.

It has been recognized that polluting organic substances are present in such liquidsewage in three phases, namely, as suspendedmatter, as colloidal matter, andas matter in true solution. A complete purification of a liquid requires the elimination therefrom of .the organic matter present in each of these forms. l

The removal of the normally suspended matter presents no difiiculty since it is susceptible of removal, either by filtration or coagulation.

Processes have heretofore been proposed for the removal of the colloidal matter, and these proc esses have met with considerable success, and

effected a material purification.

Since the reduction in the bio-chemical oxygen demand is the desideratum of every purification process, it becomes important to eliminate not only the suspended matter and the collodial mat-' ter, but also the matter in true solution, espe cially in concentratedisewag or like liquids,

, wherein the true solution fraction of the organic matter increases the ultimate bio-chemical oxygen demand. f This invention accordingly contemplates the provision of a process for removing in a single as continuous treatment substantially all of-the polluting matter from a liquid, which process embraces the steps of flocculating the colloidal matter to render it susceptible of coagulation adsorbing the organic matter in true solution by an' 40 adsorbent agent, also susceptible of coagulation,

and finally coagulating the normally suspended matter, the suspended ma 1' formed .as' a result of the flocculating oi the colloid, and the adsorbeint carrying the matter adsorbed from true solu- It is a further and more specific object or the invention to eflect the flocculation of the colloids in a more economical and expeditious manner than any heretofore proposed. Y

Other and further objects of the invention will become apparent as the description of the process is developed.

For the purposes of this specification, the m1- lcwlng lines 01 demarkation between the sus- .pended matter, colloidal matter and matter in (CH. arc-2) true solution will be observed. The suspende matter includes all particles insoluble in tl medium, the s est of which do not exhib the Brownian movement; the colloidal matter in cludes all particles ranging in size from. ti largest particleswhich do exhibit the Brownir movement to the largest particles oi? a true sol1 tion which do not diffuse or dialyze; th' matt in true solution comprises the crystaloids whi1 diffuse and dialyze.

The relative putrescibility of the difierent ira tions of the organic matter present in a pollute liquid is indicated by the percent of the ten d: bio-chemical oxygen demand attributable to em fraction. In normal sewage these percentag are about as follows:

Suspended matter 35% of the 10 day B. 0. Colloidal matter 53% of the 10 day B. O. Dissolved matter 12% (3f the 10 day B. 0.

In normal sewages of low concentration, t] fraction of organic matter in true solution do not present such aserious problem, particular if the'suspended fraction and the colloidal ire. tion are efiiciently removed. However, in co: cent'rated sewage and polluted liquids, many which have a bio-chemical oxygen demand from 800 to 1200 parts per million, and in sor instances of polluted liquids, for example whe a bio-chemical oxygen demand running into se eral thousand partsper million, the true sol tion fraction assumes great importance. Wi such concentrated liquids, a process failing of r moval of the true solution fraction yields an elll ent, having a'high bio-chemical oxygen demal andone which places a heavy burden on the r ceiving stream. It is to the treatment of the concentrated liquids that the instant process I! especial application.

Since little difficulty is encountered in the l moval of suspended matter from a liquid, it l: comes apparent that if the colloidal matter, at the matter in true solution can be brought in a state of suspension, it may likewise be remov with little difilculty. When colloids are flocculs ed, they take on the character of suspended in: ter, and become susceptible of coagulation.

I have, ascertained that it is also possible adsorb from the polluted liquid matter in tr solution by utilizing an adsorbing agent which susceptible of coagulation. i. am able to efii flocculation of the colloids, as well as adsorpti of the matter in true solution, in the preser of the suspended. matter. it will-thus be sc that by efiecting flocculation oi the colloid, a 

